<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<canvas id="myCanvas" width="1000" height="500"></canvas>
<script type="text/javascript">
var c=document.getElementById("myCanvas");
var cxt=c.getContext("2d");
cxt.fillStyle="#FF0000";
cxt.fillRect(0,0,150,75);
</script>
</body>
</html>